Radiant thermal barrier

ABSTRACT

Fan-folded panels are provided with longitudinal cuts or fold lines along an extended length of the panels to enable folding of edge sections of the panels into channel walls on either side of an intermediate panel section together forming a channel having a heat reflective surface inside the channel, the channel for insertion between two facing joists or studs so that tops of the channel walls are pushed up against a facing surface supported by the joists to form an air cavity between the facing surface and the channel acting as the radiant thermal barrier. A hydronic under floor heating pipe may be pre-installed attached to the facing surface supported by the joists or studs with the result that a proper air cavity is maintained with the radiant thermal barrier.

BACKGROUND OF THE INVENTION

The present invention relates to a radiant heat transfer barrier and, more particularly, to such a barrier that is useful in creating a continuous reflective dead air cavity.

Heat transfer through building structures occurs through convection conduction and radiation. In order to retard heat flow by conduction and convection, walls and roofs are built within internal air spaces. Conduction and convection through the air spaces combined represents only 20 to 35 percent of the heat which passes through them. In both winter and summer 65 to 80 percent of the heat that passes from a warm wall to a colder wall or through a ventilated attic does so by radiation.

An increasingly popular form of heating called hydronic heating can be deployed for instance by means of pipes embedded in or affixed behind or under floors, walls, ceilings, etc. between joists or studs. These pipes carry heated water that conduct warmth to the surface of the structure where it broadcasts energy into the living space. To make the system more efficient it is desirable to re-direct energy that is radiated away from the system pipes away from the area to be heated back toward that area. For example, if a radiant floor system is installed under the floorboards above an unheated basement or crawl space, insulation is required in order to isolate the heated floor from the colder space below. It is important to also create an air cavity within which the pipe or pipes reside. A reflector may be laid on the bottom of the cavity on top of the insulation that fills the remainder of the joist bay. The ideal spacing for such a reflector is three-quarter inch or more below the floorboards. Thus, a “radiant thermal barrier system” (RTBS) is in general a building section that includes a radiant barrier facing a dead air space.

Radiant barrier materials may be formed of aluminum foil laminates in which the foil is laminated to kraft paper, card board, plastic films or to OSB/plywood roof sheathing. Or another variation is aluminized plastic films comprising a thin layer of aluminum particles deposited on film through a vacuum process. In both cases, the heat reflective insulation is provided by low emittance surfaces bounding one or more enclosed air spaces. As mentioned, below the reflective radiant thermal barrier material fiberglass or other similar kinds of insulation may be placed to reduce heat transfer between the cavity and the cooler space below (such as a basement).

A typical way to try to create an air cavity for instance between a pair of overhead joists is to loosely place a layer of aluminum foil on top of fiberglass and push the fiberglass with aluminum foil loosely lying on top into the joist bay but not all the way in so as to try to leave a small air space, with the aluminum foil facing the floor board so that radiant heat coming from a pipe installed under the floor and inside the cavity reflects back off the aluminum foil toward the floor board rather than toward the basement. The fiberglass insulation resists additional heat loss through convection and conduction toward the basement.

A problem with this method of installation of a radiant reflective barrier is that it is not easy to judge the proper amount of insertion of the insulation so as to maintain the at least three-quarters to one inch of air space needed to create a proper air cavity between the pipe attached to the floor and the reflective foil lying on top of the fiberglass batting below. A similar problem exists between studs in forming an air cavity for the same or any similar purpose for a wall or a ceiling or for forming a cavity between roof joists and an attic.

SUMMARY OF INVENTION

It is an object of the invention to provide a combination convective/conductive radiant thermal barrier that is easy to install and provides a consistent air space without difficulty.

According to a first aspect of the present invention, a laminated board is provided of any lightweight construction material having longitudinal cuts along an extended length of the board to enable folding of edge sections of the board into channel walls on either side of an intermediate panel section and forming a channel having a thermal radiant reflective laminar skin inside the channel for insertion between two facing joists or studs so as to be pushed up against a facing surface to form an air cavity including said channel acting as said radiant thermal barrier. Insulation such as fiberglass may then be installed below the radiant thermal barrier.

The longitudinal cuts of the radiant thermal barrier may comprise two pairs of longitudinal cuts including an outer pair cut through the laminar skin on only one side of the adjacent planar sections and an inner pair cut through the laminar skin on the other side of the adjacent planar sections so that the extended length of board is foldable along the inner pair of longitudinal cuts to form an inner layer of the channel walls and is foldable along the outer pair of longitudinal cuts to form an outer layer of the channel walls with the outer layer extending beyond the inner layer so as to form a protruding section that is fastenable to the facing joists or studs.

The heat reflective laminar skin inside the channel may be a metalized laminar skin such as aluminum or any low emissivity surface or coating that reduces radiant energy absorption.

The laminated board may be made of foam such as styrofoam or another plastic material such as extruded polyethylene having a honeycomb core. The laminated board may also be of any other lightweight construction material such as cardboard.

The laminated board may be laminated on both sides with laminar skins and provided with alternating transverse cuts that cut through only one laminar skin, the uncut skin acting as a hinge between adjacent planar sections of the laminated board to enable fan-folding of the laminated board for packaging and transport.

According to a second aspect of the present invention, a thermal panel comprises a first side and an opposing second side with a first edge on the first side and a second edge on the second side and four folding lines substantially parallel to both the first edge and the second edge, the four folding lines comprising a first inner folding line provided on the first side, a first outer folding line provided between the first inner folding line and the first edge, a second inner folding line provided on the second side and a second outer folding line provided between the second inner folding line and the second edge, wherein the four folding lines partition the panel into a plurality of portions comprising a first edge portion between the first edge and the first outer folding line, a first intermediate portion between the first outer folding and the first inner folding line, a middle portion between the first inner folding line and the second inner folding line, a second intermediate portion between the second outer folding line and the second inner folding line, and a second edge portion between the second edge and the second outer folding line, such that when a force is applied about the first outer folding line and about the second outer folding line in a direction substantially perpendicular to the middle portion, the panel is folded into a shape having the middle portion between a first wall on the first side and a second wall on the second side, with the first wall made of the first intermediate portion and the first edge portion, and a second wall made of the second intermediate portion and the second edge portion.

The thermal panel according to the second aspect of the present invention may comprise any lightweight thin rectangular lightweight board material such as plastic, foam, styrofoam, card board or the like.

The material may be cut as in the first embodiment of the invention or may have the four folding lines compressed into the material by means for example of a heated die to enable easy folding. The folding lines may also be created by any suitable methodology which would allow construction personnel to fold-over the edge and intermediate portions to form the first and second walls.

These and other objects, features and advantages of the present invention will become apparent in light of the detailed description of a best mode embodiment thereof as illustrated in the accompanying drawing.

GRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a fragmentary plan view of an unfolded board with cuts or with fold lines according to the present invention.

FIG. 2 a is a section view of the unfolded board of FIG. 1 that is laminated and cut according to a first embodiment of the present invention.

FIG. 2 b shows a folding operation in which the laminated board of FIG. 2 a is folded in one direction along its extended length along an inner pair of longitudinal cuts to form an inner channel wall layer on each side and folded in an opposite direction along an outer pair of longitudinal cuts to form an outer layer of the channel walls.

FIG. 2 c shows the finished folding operation started as shown in FIG. 2 b with the outer layers of the channel walls extending beyond the inner layer so as to form a protruding section below the planar section.

FIG. 3 shows the longitudinally folded radiant thermal barrier of FIG. 2 c inserted between two facing joists or studs with the tops of the channel walls pushed up against a facing surface such as a floor to form an air cavity including the radiant thermal barrier.

FIG. 4 shows the adjacent planar sections of the laminated foam board of FIG. 1 fan-folded into a block that is easily packaged and transported to construction sites.

FIG. 5 a is a section view of the unfolded board of FIG. 1 that has fold lines according to a second embodiment of the present invention.

FIG. 5 b shows a folding operation in which the board of FIG. 5 a is folded in one direction along its extended length along an inner pair of longitudinal fold lines to form an inner channel while layer on each side and folded in an opposite direction along an outer pair of longitudinal fold lines to form an outer layer of the channel walls.

FIG. 5 c shows the finished folding operation started as shown in FIG. 5 b with the outer layers of the channel walls extending beyond the inner layer so as to form a protruding section below the planar section.

FIG. 6 shows the longitudinally folded radiant thermal barrier of FIG. 5 c inserted between two facing joists or studs with the tops of the channel walls pushed up against a facing surface such as a floor to form an air cavity including the radiant thermal barrier.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT

Turning first to FIG. 1, a radiant heat barrier 10 is shown according to the first embodiment of the present invention comprising an extended length of sectional panels 20 such as laminates of a card board or of a synthetic resin foam board such as polystyrene or polyurethane or of any lightweight construction material usually formed into a thin, rectangular panel or board. Laminar skins may be applied on each planar surface thereof to form the laminate board. The laminar skins may be inherent in the material of the panels or board itself. The laminar skins provide rigidity and integrity for the unfolded planar sections of building panels in the unfolded state of FIG. 1 in its extended length. Such skins may be fabricated of synthetic resin film and one or both of the skins may be metalized.

The radiant thermal barrier 10 shown in its extended length in FIG. 1 is shown with a series of transverse cuts 41, 42 spaced along the extended length. In the production process, alternating cuts 41 may be scored or cut through alternate surfaces to a depth short of the laminar skin on the other surface so as to form a transverse hinge by means of the remaining laminar skin. The same is done on the other side on alternating transverse scoring or cuts 42 so as to provide the fan-folding feature to be described below in connection with FIG. 4.

FIG. 1 shows longitudinal cuts 31, 31′, 33, 33′ of the laminated board that are perpendicular to the transverse cuts 41, 42 with each cut 31, 31′, 33, 33′ through only one laminar skin to enable folding of edge sections 22, 24 of the planar sections into channel walls, to be described later on. This may be done as shown with two pairs of longitudinal cuts including an outer pair 33, 33′ through the laminar skin on only one surface of the adjacent planar sections and an inner pair 31, 31′ cut through the laminar skin on the other surface of the adjacent planar sections. This permits folding of the edge sections 22, 24 into channel walls (see walls 42, 44 of FIG. 2 c) having a heat reflective laminar skin inside a channel formed by the inner planar sections 20 and the edge sections 22, 24 and 22′, 24′ folded along the longitudinal cuts to form channel walls.

FIG. 2 a shows a sectional view of the extended panel of FIG. 1 before formation of the channel of FIG. 2 c. It includes a main channel inner part comprising panel sections 20, an inner channel wall section 24, 24′ along an inner edge part of the board and an outer channel wall section 22, 22′ along an outer edge part of the board. The two pairs of longitudinal cuts 31, 31′ and 33, 33′ are shown on either side of the inner part of the board. The outer pair cuts 33, 33′ are cut through the laminar skin on only the top surface of each adjacent planar section 20. The cut is to such a depth in the board that it does not cut through the laminar skin on the bottom surface. Likewise, the inner pair cuts 31, 31′ are cut through only the laminar skin on the other (bottom) surface of the adjacent planar sections and through the board down to a depth that does not cut through the laminar skin on the top side.

The act of forming the channel walls is shown in FIGS. 2 a and 2 b carried out by exerting forces indicated by heavy bold face arrows. As shown in FIG. 2 a by two bold face arrows on each side, an upward force applied about the outer longitudinal cuts 33, 33′ and a downward force about the inner longitudinal cuts 31, 31′ in a direction substantially perpendicular to the inner planar sections 20 of the board results in the outer edge parts 22, 22′ of the board being folded downward as shown in FIG. 2 b and the inner edge parts 24, 24′ being folded upward. Likewise, as shown by two horizontal bold face arrows in FIG. 2 b, a pushing force on each side 12, 14 is then made to cause the inner edge parts 24, 24′ and the outer edge parts 22, 22′ to be pushed together alongside each other to form opposing channel walls 42, 44 on opposite sides of the panel sections 20 and at right angles thereto as shown in completed form in FIG. 2 c. Thus, the extended length of board is folded along the inner pair of longitudinal cuts 31, 31′ so as to form an inner layer of the channel walls with the inner edge parts 24, 24′, as shown completed in FIG. 2 c. Similarly, the extended length of board is shown being folded along the outer pair of longitudinal cuts 33, 33′, as shown in FIG. 2 b to form an outer layer of the channel walls 42, 44 with the outer edge parts 22, 22′ as best shown in completed form in FIG. 2 c.

According to the embodiment illustrated, the outer layer made from the outer edge sections 22, 22′ may be formed of such a length L₂ so as to extend downward beyond the shorter length L₁ of the inner layer 22 below a main inner part of the channel comprising the panel sections 20 so as to form a protruding length of that edge section 24 below the bottom of the channel inner part.

The radiant thermal barrier shown in FIG. 2 c may have an outside dimension W that matches a standard inside dimension of a joist bay shown in FIG. 3, i.e., the length between the two inner facing surfaces of joists 110. As mentioned above, the depth of the channel is shown in FIG. 2 c as having a length L₁ which may be on the order of three-quarters of an inch to one inch for an ideal spacing. Again, the length of the edge sections 22, 22′ is indicated in FIG. 2 c as having a length L₂ which may be on the order of two or three inches for instance to provide for sufficient protrusion to allow fasteners such as staples to be used to fasten the barrier to the facing sides of the joists 110.

FIG. 3 shows the radiant thermal barrier 10 of FIG. 2 c inserted between the two facing joists 110 or studs with the tops of the channel walls pushed up against a facing under-surface of the floor surface 100 to form an air cavity 120 including the radiant thermal barrier on three sides thereof. A radiant heat pipe or pipes 130 may be affixed to the under-surface of the facing under-surface of the floor 100 inside the air cavity.

As mentioned, the protruding section of edge section 24 may be used as a surface with which to staple or otherwise fasten the radiant thermal barrier to the inner faces of the joists or studs. Insulation in the form for instance of fiberglass batting may then be pushed into the remaining part of the space between the joists underneath the radiant thermal barrier and affixed to the joists for providing further insulation, mainly against convection of heat from the cavity to e.g., an unheated space such as a basement below.

FIG. 4 shows the adjacent sectional panels or planar sections 20 of FIG. 1 in a folded condition for instance at the factory for packaging or after packaging for transport to a construction site. The stack may of course be much thicker and contain many more layers than pictured in FIG. 4 so as to form a block of folded panels 20 e.g. of synthetic resin foam board with laminar skin adhered to each planar surface thereof block form is easily packaged and transported. Once it arrives at the construction site, the outer packaging may be removed and the planar sections 20 unfolded into a length of board suitable to extend along the entire length of the bay between the joists or the studs to be insulated. This could be done by unfolding the block of sections to form an extended board and cutting the extended board to size before carrying out the operation shown in FIG. 2 b and 2 c so as to be readily insertable by one or more construction workers as shown in FIG. 3 using perhaps staple guns to affix the entire length of the extended board between two facing joists e.g. with pipes 130 already installed (if such is the application).

It should be mentioned again that the transverse cuts 41, 42 and the longitudinal cuts 31, 33 need not be cut all the way through the board to a depth short of the protective film on the other surface but rather may be scored instead on alternate surfaces so as to permit hand-breaking between adjacent panels upon a folding force being applied thereto during the folding part of the manufacturing process in which a block is formed as suggested in FIG. 4.

Furthermore, according to a second embodiment of the present invention, there need not be any cuts at all. Rather, the cuts described above in connection with the first embodiment may instead be folding lines pressed into the surface of the material such as by means of a heated die e.g. with a v-shaped knife edge or even a rounded edge. By compressing the lightweight construction material such as cardboard with such a die the folding lines would not actually constitute cuts in the material but would rather merely be impressed into the material to facilitate fan-folding along the transverse folding lines at the factory and after unfolding at the construction site, to likewise facilitate hand-folding along the longitudinal folding lines. Thus, as shown in FIG. 1, the alternating transverse folding lines 41, 42 are pressed into at least one surface of the lightweight construction material for enabling fan-folding in the factory. Likewise, the outer pair of longitudinal folding lines 33, 33′ may be pressed into the material on one surface while the inner pair 31, 31′ are pressed into the other surface. It should be emphasized that the lines do not have to be impressed alternately on opposite surfaces but may be impressed on only one surface of the panels as a matter of design choice.

FIG. 5 a shows a sectional view of the extended panel of FIG. 1 before formation of the channel of FIG. 5 c using a material with folding lines pressed according to the second embodiment of the present invention. Instead of the cuts of FIG. 2 a, FIG. 5 a shows v-shaped indentations pressed into the material of the board. The board includes a main channel inner part comprising a central part of panel sections 20 between inner folding lines 31, 31′, an inner channel wall section 24, 24′ along an inner edge part of the board and an outer channel wall section 22, 22′ along an outer edge part of the board. As mentioned, the two pairs of longitudinal folding lines 31, 31′ and 33, 33′ are shown in a non-limiting way on opposite surfaces of the board as indentations instead of cuts. The outer pair of folding lines 33, 33′ may be impressed as shown on only the bottom surface of each adjacent planar section 20. Likewise, the inner pair of folding lines 31, 31′ may reside only on the other (bottom) surface of the adjacent planar sections.

The act of forming the channel walls is shown in FIGS. 5 a and 5 b. As shown in FIG. 5 a by two boldface arrows, an upward force applied about the outer longitudinal folding lines 33, 33′ and a downward force applied about the inner longitudinal folding lines 31, 31′ each force applied in a direction substantially perpendicular to the inner planar sections 20 results in the outer edge parts 22, 22′ of the board being folded downward as shown in FIG. 5 b and the inner edge parts 24, 24′ being folded upward. Likewise as shown by two horizontal boldface arrows in FIG. 5 b, a pushing force is then made toward the edges 32, 34 to cause the inner edge parts 24, 24′ and the outer edge parts 22, 22′ to be pushed together adjacent each other to form opposing channel walls 42, 44 on opposite sides 12, 14 of the panel sections 20 and at right angles thereto as shown completed in FIG. 5 c. Thus, the extended length of board is folded along the inner pair of folding lines 31, 31′ so as to form an inner layer of the channel walls with the inner edge parts 24, 24′, as shown completed in FIG. 5 c. Similarly, the extended length of board is shown being folded along the outer pair of longitudinal folding lines, as shown in FIG. 5 b to form an outer layer of the channel walls 42, 44 with the outer edge parts 22, 22′ as best shown completed in FIG. 5 c.

Similar to the first embodiment, the second embodiment also may include the outer layer made from the outer edge section 22, 22′ formed of such a length L₂ so as to extend beyond the shorter length L₁ of the inner layer 24, 24′ below the main channel inner part 20 of the channel and thus form a protruding length of that edge section 22, 22′ to facilitate fastening.

As also with the first embodiment, the radiant thermal barrier of the second embodiment shown in FIG. 5 c may have an outside dimension W that matches a standard inside dimension of a joist bay shown in FIG. 6, i.e., the length between the two inner facing surfaces of joists 110. The depth of the channel is shown in FIG. 5 c as having the length L₁ which may be on the order of three-quarters of an inch to one inch for an ideal spacing. The length of the edge sections 24, 24′ is indicated in FIG. 5 c as having the length L₂ which may be on the order of two or three inches for instance to provide for sufficient protrusion to allow fasteners such as staples to be used to fasten the barrier to the facing sides of the joists.

FIG. 6 shows the radiant thermal barrier 10 of FIG. 5 c inserted between the two facing joists 110 or studs with the tops of the channel walls pushed up against a facing under-surface of the floor surface 100 to form an air cavity 120 including the radiant thermal barrier on three sides thereof. A radiant heat pipe or pipes 130 may be affixed to the under-surface of the facing under-surface of the floor 100 inside the air cavity.

As mentioned, the protruding section of edge sections 22, 22′ may be used as a surface with which to staple or otherwise fasten the radiant thermal barrier to the inner faces of the joists or studs. Insulation in the form for instance of fiberglass batting may then be pushed into the remaining part of the space between the joists underneath the radiant thermal barrier and affixed to the joists for providing insulation, mainly against convection of heat from the cavity to e.g. an unheated basement below.

Referring back to FIG. 1, according to both the first and second embodiments of the present invention, the thermal panel may be said to have has a first side 12 and an opposing second side 14. The words “folding lines” should be understood as covering cuts or scored lines as well as impressed lines in the discussion that follows. A first edge 32 on the first side corresponds to a second edge 34 on the second side. Four folding lines 31, 31′ and 33, 33′ are laid out substantially parallel to both the first edge 32 and the second edge 34. The four folding lines include a first inner folding line 31 provided on the first side, a first outer folding line 33 provided between the first inner folding line 31 and the first edge 32, a second inner folding line 31′ provided on the second side, and a second outer folding line 33′ provided between the second inner folding line 31′ and the second edge 34, wherein the four folding lines partition the panel into a plurality of portions.

These portions include a first edge portion 22 between the first edge 32 and the first outer folding line 33, a first intermediate portion 24 between the first outer folding line 33 and the first inner folding line 31, a middle portion 20 between the first inner folding line 31 and the second inner folding line 31′, a second intermediate portion 24′ between the second outer folding line 33′ and the second inner folding line 31′, and a second edge portion 22′ between the second edge 34 and the second outer folding line 33′.

Referring again to FIG. 2 a and to FIG. 5 a, as described previously above, it can be said that when a force is applied about the first outer folding line 33 and about the second outer folding line 33′ (shown as an upward force in FIG. 2 a and in FIG. 5 a for example) in a direction substantially perpendicular to the middle portion 20 the panel is folded into a shape having the middle portion 20 between a first wall 42 (see FIG. 5 c or FIG. 2 c) on the first side 12 and a second wall 44 on the second side 14, with the first wall 42 made of the first intermediate portion 24 and the first edge portion 22, and the second wall 44 made of the second intermediate portion 24′ and the second edge portion 22′. Naturally, at the same time as applying the perpendicular force in an upward direction as shown in FIG. 2 a or FIG. 5 a, the first and second intermediate portions 24, 24′ fold in an upward direction as shown in FIG. 2 a or in FIG. 5 b along the inner folding lines 31, 31′ as shown by the downward arrows of FIG. 2 a or FIG. 5 a. A horizontal force is exerted as shown in FIG. 2 a or FIG. 5 b to cause the folded portions 22, 24′ and 22′, 24′ to come together to form the first wall 42 on the first side and the second wall 44 on the second side 14. In this way, the first wall 42 is made up of the first intermediate portion 24 and the first edge portion 22 and the second wall 44 as made up of the second intermediate portion 24′ and the second edge portion 22′.

Although the invention has been shown and described with respect to a best embodiment thereof, it should be understood by those skilled in the art that the foregoing and various other changes, omissions and deletions in the form and detail thereof may be made therein without departing from the spirit and scope of the invention. 

1. A radiant thermal barrier, comprising an extended length of board having a laminar skin adhered to each planar surface of said board to form a laminated board, said laminated board having a series of transverse cuts spaced along said extended length through said laminated board and alternately through only one laminar skin, the uncut skin acting as a hinge between adjacent planar sections of said laminated board to enable fan-folding of said laminated board, said laminated foam board having longitudinal cuts perpendicular to said transverse cuts, each cut through only one laminar skin to enable folding of edge sections of said planar sections into channel walls with said board unfolded and extended into said extended length, said channel walls having a heat reflective laminar skin inside a channel formed by said adjacent planar sections and said channel walls folded along said longitudinal cuts for insertion between two facing joists or studs up against a facing surface to form an air cavity including said radiant thermal barrier.
 2. The thermal heat barrier of claim 1, wherein said longitudinal cuts comprise two pairs of longitudinal cuts including an outer pair cut through the laminar skin on only one side of said adjacent planar sections and an inner pair cut through the laminar skin on the other said of said adjacent planar sections so that said extended length of board is foldable along said inner pair of longitudinal cuts to form an inner layer of said channel walls and is foldable along said outer pair of longitudinal cuts to form an outer layer of said channel walls with said outer layer extending beyond said inner layer so as to form a protruding section that is fastenable to said facing joists or studs.
 3. The radiant thermal barrier of claim 1, wherein said heat reflective laminar skin inside said channel is a metalized laminar skin.
 4. The radiant thermal barrier of claim 1, wherein said heat reflective laminar skin is metalized with aluminum.
 5. The radiant thermal barrier of claim 1, wherein said heat reflective laminar skin is aluminum foil.
 6. A thermal panel, comprising: a first side and an opposing second side, a first edge on the first side, a second edge on the second side, and four folding lines substantially parallel to both the first edge and the second edge; said four folding lines comprising: a first inner folding line provided on the first side; a first outer folding line provided between the first inner folding line and the first edge; a second inner folding line provided on the second side; and a second outer folding line provided between the second inner folding line and the second edge, wherein the four folding lines partition the panel into a plurality of portions comprising; a first edge portion between the first edge and the first outer folding line; a first intermediate portion between the first outer folding line and the first inner folding line; a middle portion between the first inner folding line and the second folding line; a second intermediate portion between the second outer folding line and the second inner folding line; and a second edge portion between the second edge and the second outer folding line, such that when a force is applied about the first outer folding line and about the second outer folding line in a direction substantially perpendicular to the middle portion, the panel is folded into a shape having the middle portion between a first wall on the first side and a second wall on the second side, with the first wall made of the first intermediate portion and the first edge portion, and the second wall made of the second intermediate portion and the second edge portion.
 7. The thermal panel of claim 6, further comprising a heat reflective surface on a surface of said thermal panel. 